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  • #16
    @onehitch
    If by "terrible antenna" you mean the mag mount whip suppled with generic dvb-t dongles, it can be substantially improved very easily by following two steps:

    (1) The magnetic base of whip provides a very tiny ground plane. Enlarge the ground plane by placing the whip over a large matallic surface like a can, plate or sheet. See photo 1 below.

    (2) The whip is too long for 1090 Mhz. Cut the whip to make it 67 mm (1/4 wavelength). The 67 mm is made up of 15 mm metal inside base + 52 mm length above base. See photo 2 below.

    Photo 1





    Photo 2

    Last edited by abcd567; 2016-05-21, 02:24.

    Comment


    • #17
      Originally posted by abcd567 View Post
      A filter is necessary in almost all cases because the Pro Stick's front end rf amplifier is a wide band amplifier, and amplifies all tv, cell/mobile phone and other signals, causing overload of dongle's tuner chip.

      Without filter, the gain of dongle has to be lowered from "max" (49.6 dB) to 30 to 35 dB to prevent overloading and saturation of dongle's front end by Cell/Mobile phone, TV, and other strong signals. This means most of gain of the pre amplifier of dongle is lost.

      With filter, the unwanted signals are rejected before reaching dongle, and gain can be set to maximum (or nearly maximum), and message rate, number of planes and maximum range increase.




      Thanks for the data. Without the filter it's worse than without the front end amplifier so I agree that it's needed.
      The only thing that worries me is how much power does it consume and how much is lost to heat. ie how hot does it feel? I don't want to worry about anything possibly catching fire in the attic .

      Edit: Also, even with the filter it doesn't seem to be much improvement over generic stick. Probably more data is needed?
      BTW: I'm concerned about how hot the USB stick runs, not the filter. If the filter is connected directly to the USB stick as shown, it's actually a heat sink but not mechanically stable without brackets and other hardware. .
      Last edited by Sam26K; 2016-05-22, 03:22.

      Comment


      • #18
        @Sam26K
        ProStick does heat up, but NOT dangerously hot.

        Pro Stick Specifications
        Chip: R820T2
        Amplifier: 19dB with 0.4dB noise figure and OIP3 +39dB
        Power Draw: 300mA
        Weight: 85g / 3oz
        Dimensions: 95mm x 32mm x 13mm
        Antenna Port: SMA female (requires SMA antenna cable and optionally N-male adapter for large antenna)
        Range: Over 275nm/500km depending on installation quality
        Performance: 20-100% range improvement for Mode S message vs traditional RTL SDR
        Computer: Raspberry Pi 3 running PiAware recommended.

        Source: http://flightaware.com/adsb/prostick/

        .
        Last edited by abcd567; 2016-05-22, 04:12.

        Comment


        • #19
          Originally posted by Sam26K View Post
          Also, even with the filter it doesn't seem to be much improvement over generic stick. Probably more data is needed?
          BTW: I'm concerned about how hot the USB stick runs, not the filter. If the filter is connected directly to the USB stick as shown, it's actually a heat sink but not mechanically stable without brackets and other hardware. .
          I found the Pro Stick increased my coverage and doesn't run any hotter than the one it replaced. And it sits on a shelf with the filer directly attached and no brackets required.

          Some comparative results here:

          Mike


          www.radarspotting.com

          Radarspotting since 2005

          Comment


          • #20
            Hi everyone! Last week I received my ProStick, and after some issues with the power supply (thank you @abcd567) now it's working good! So, I did the range plot with both, the ISDB-T Dongle and the ProStick. I noticed that my range increased a little, but nothing significant! I use with a CanTenna and a raspberry Pi B+, coaxial cable distance is less than 40 centimeter (15,74 inches), with a 1090mhz filter! I got this stick for free because the team from FlightAware are not able to sent a full ADB-S station to Brazil at this time!

            CanTenna+Filter+ISDB-T Dongle (each circle range have 50km/31.06Miles)
            ISDB-T.png

            CanTenna+Filter+ProStick (each circle range have 50km/31.06Miles)
            ProStick.png
            T-SBCT5/T-SBCT6

            Comment


            • #21
              @dudesjp
              Did you adjust the gain of dump1090? The default "max" is 49.6 dB. Try 45 dB and then 42 dB, most likely it will improve your range.

              If you have dump1090-mutability, use this command to change gain setting.
              Code:
              sudo dpkg-reconfigure dump1090-mutability
              See this page:
              http://flightaware.com/adsb/prostick/setup/

              .
              Last edited by abcd567; 2016-07-07, 17:11.

              Comment


              • #22
                Originally posted by dudesjp View Post
                I noticed that my range increased a little, but nothing significant!
                Looking at your two polar diagrams, it looks like you've gained some useful extra range. That assumes the second one is using the Pro Stick?

                I'd be very pleased to see that amount of gain, especially from a free receiver.
                Mike


                www.radarspotting.com

                Radarspotting since 2005

                Comment


                • #23
                  Originally posted by abcd567 View Post
                  @dudesjp
                  Did you adjust the gain of dump1090? The default "max" is 49.6 dB. Try 45 dB and then 42 dB, most likely it will improve your range.

                  If you have dump1090-mutability, use this command to change gain setting.
                  Code:
                  sudo dpkg-reconfigure dump1090-mutability
                  See this page:
                  http://flightaware.com/adsb/prostick/setup/

                  .
                  I Didn't! Yes, I have the Mutability one, I'll try this then! Thank you

                  Originally posted by Anmer View Post
                  Looking at your two polar diagrams, it looks like you've gained some useful extra range. That assumes the second one is using the Pro Stick?

                  I'd be very pleased to see that amount of gain, especially from a free receiver.
                  With this new tip from @abcd567, let's try and see if gets better!
                  T-SBCT5/T-SBCT6

                  Comment


                  • #24
                    @maxxtech
                    The FA Antenna+FA Filter+ProStic is the best option I have used up to now.

                    I have 2 setups. My stats show the FA combo gives much better performance: Message rate 182%, Plane count 114%

                    Pi-1: Cantenna + 12 ft RG6 Coax + 12 inch RG316 pigtail + Black DVB-T (No Amplifier) >> plugged directly into OPi PC
                    Pi-2: FA Antenna + 4 ft RG6 Coax + 4 inch RG316 pigtail + FA Filter + ProStick >> plugged directly into RPi Model2

                    Note:
                    (1) Both antennas are at same location in same vertical line. Horizontal distance = 0, Vertical distance = 1 m / 3 ft
                    (2) There is NO AMPLIFIER with Cantenna + Generic DVB-T, while ProStick has a built-in RF amplifier.




                    Comment


                    • #25
                      @maxxtech
                      Range greater than 300 is shown on FR24, but my local data monitoring on Ras Pi / dump1090 restricts data to 300 nm. See below range figures on graphs generated locally on RPi, and Polar Graphs generated by FR24:

                      LOCAL GRAPHS








                      FR24 POLAR CURVES



                      ================================================== =================





                      .

                      Comment


                      • #26
                        Shouldn't the real test be the difference between the two different DVB-T sticks? The FA antenna has 6dB gain. Would like to see a comparison between a typical ADSB stick with FA antenna and the FA pro stick with filter, and same FA antenna and cables. That would show if it is worth the extra expense and higher power consumption.

                        Edit: BTW abcd567, how did you get that range with that antenna setup in the pics? Do you live in a lighthouse?
                        Last edited by Sam26K; 2016-07-11, 06:28.

                        Comment


                        • #27
                          Originally posted by Sam26K View Post
                          Would like to see a comparison between a typical ADSB stick with FA antenna and the FA pro stick with filter, and same FA antenna and cables.
                          I ran a comparative back in April when the Pro Stick was launched and you can see the results here:



                          Both sharing the same FA antenna using an RF Systems SP3 splitter. To make it an even contest, I used an FA filter with each DVB-T.
                          Mike


                          www.radarspotting.com

                          Radarspotting since 2005

                          Comment


                          • #28
                            Originally posted by Sam26K View Post
                            Shouldn't the real test be the difference between the two different DVB-T sticks? The FA antenna has 6dB gain. Would like to see a comparison between a typical ADSB stick with FA antenna and the FA pro stick with filter, and same FA antenna and cables. That would show if it is worth the extra expense and higher power consumption.
                            My DVB-T usb dongle (black) is connected to Cantenna, and ProStick+Filter to FA antenna.

                            Once I swapped Cantenna & FA antenna, and performance of BOTH systems dropped . I checked all connection, all was ok.

                            I think the reason is simple, but not obvious. The DVB-T dongle is designed for TV, and its input impedance (front end tuner chip R820T) has standard TV impedance of 75 ohms. The Cantenna also has an impedance of 70 ohms, so this makes a good impedance match.

                            The Pro Stick's also has the tuner chip R820T2 with input impedance of 75 ohms, but it is not the front end. The front end is a RF amplifier chip which has an input impedance of 50 ohms. Also the Filter and FA antenna have 50 ohms impedance. Hence FA antenna+Filter+ProStick make a perfect impedance match.

                            By swapping FA antenna with Cantenna, my both system suffered from impedance mismatch 75 combined with 50 ohms, and hence performance of both dropped.


                            Edit: BTW abcd567, how did you get that range with that antenna setup in the pics? Do you live in a lighthouse?
                            Umm..., yes, equivalent of a lighthouse .

                            I live in an apartment in a tall building. My apartment is about 50 feet above the road level, and I have my antennas placed near U shaped tall and wide glass window (i.e. antennas can see about 270 degrees out of 360 degrees). The window is not obvious in photo as only a small part of it was captured by the camera, and that also is hidden behind vertical blinds.

                            The window/lighthouse is more obvious in photos in these two posts:

                            1) Trial Run Results for Three Types of Whip Antennas


                            2) Trial Run Results for Four Sizes of Ground Planes
                            Last edited by abcd567; 2016-07-11, 16:20.

                            Comment


                            • #29
                              Originally posted by abcd567 View Post
                              @dudesjp
                              Did you adjust the gain of dump1090? The default "max" is 49.6 dB. Try 45 dB and then 42 dB, most likely it will improve your range.

                              If you have dump1090-mutability, use this command to change gain setting.
                              Code:
                              sudo dpkg-reconfigure dump1090-mutability
                              See this page:
                              http://flightaware.com/adsb/prostick/setup/

                              .
                              After change the gain, here's the new plot! A little bit better! Next step is buy a professional antenna (flightaware or fr24), to see if my range increase!

                              Raspberry Pi B+/Cantenna/Prostick/Flightaware Filter/Gain "max"
                              ProStick.png

                              Raspberry Pi B+/Cantenna/Prostick/Flightaware Filter/Gain 45dB
                              ProStick 2.png
                              T-SBCT5/T-SBCT6

                              Comment


                              • #30
                                Originally posted by abcd567 View Post
                                The Pro Stick's also has the tuner chip R820T2 with input impedance of 75 ohms, but it is not the front end. The front end is a RF amplifier chip which has an input impedance of 50 ohms. Also the Filter and FA antenna have 50 ohms impedance. Hence FA antenna+Filter+ProStick make a perfect impedance match.
                                Ok, thanks for that info. The impedance matching is a huge factor in receiver performance. Especially if there is a long run of antenna cable. For that reason alone, the FA Pro Stick is worth the extra expense.

                                Update: Just tried to buy online and unavailable on Amazon. DejaVu?

                                There is this link that's selling the ProStick with the whole FA antenna package. Great deal if you don't already have the antenna.
                                https://www.amazon.com/dp/B01F8DQV24?psc=1
                                Last edited by Sam26K; 2016-07-12, 06:20.

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